1. Field of the Invention
This invention relates to a displacement sensing apparatus in general and more particularly to a displacement sensing apparatus which can output a signal corresponding to the position of a slider that can be slid or moved over a circuit board in response to the movement of any kind of a position-detectable part.
2. Description of the Related Art
A displacement sensing apparatus can be used to detect the position of a translatable or rotational part. Japanese Patent Application Laid-Open No. HEI 9-311012 shows one kind of such apparatus including a first slider and a second slider, both of which can slide over a circuit board. The first slider and the second slider are configured so as to maintain their angles to the circuit board. So, they can slide while keeping the angles.
A first voltage generating circuit generates a first output voltage corresponding to the position of the first slider on the circuit board. A second voltage generating circuit generates a second output voltage corresponding to the position of the second slider on the circuit board. A the second output voltage from the second voltage generating circuit tends to increase and decrease in the same manner as the first output voltage from the first voltage generating circuit. Based on both of the first and the second output voltages, the apparatus can detect the position of the rotational part.
However, the first slider and the second slider may be influenced by various kinds of vibrations or forces from outside. This makes it makes it difficult for both the first and the second sliders to keep their configuration angles to the circuit board. In other words, it may happen that the configuration angles of both sliders become changed. And when the configuration angles are changed, the positions of both the first and the second sliders are consequently changed. Therefore, the first output voltage and the second output voltage can be influenced in such situations.